This invention relates to a crystalline ring-opened norbornene polymer having improved processability and shapability; a crystalline hydrogenation product of ring-opened norbornene polymer; and processes of the polymer and the hydrodrogenation product thereof.
Ring-opened norbornene polymers and hydrogenation products thereof are known as non-crystalline polymers. For Example, a polymer of dicyclopentadiene, i.e., a tricyclic norbornene monomer, is reported which is made by polymerization conducted by using a catalyst Mo(N-2,6-C6H3-i-Pr)-(CHC(CH3)2Ph) (OCCH3(CF3)2)2 [for example, J. Mol. Cat. A:Chem., 133, 67-74 (1998)]. According to the analysis carried out by the present inventors, this polymer was proved not to possess a melting point and was a non-crystalline polymer.
This polymer exhibits good transparency, heat resistance, birefringence, and processability and shapability. Therefore, it was proposed to use this polymer as a material for optical disks and optical lenses. Further, this polymer exhibits reduced dielectric and enhanced chemical resistance. Therefore, it was also proposed to apply this polymer in fields other than optical applications. However, this polymer is often unsuitable for use in a field in which high mechanical strength and high solvent resistance are required.
A part of ring-opened norbornene polymers and their hydrogenation products are crystalline. For example, a hydrogenation product of ring-opened polymer of 2-norbornene which is a dicyclic norbornene monomer was reported as a crystalline polymer having a melting point of 116xc2x0 C. (Polymeric Materials Science and Engineering, vol. 76, p61 (1997), American Chemical Society. The melting point of this hydrogenation product was very low and thus the heat resistance was poor.
Further, it was reported that a polymer made by polymerizing 5-trifluoromethyl-5,6,6-trifluoro-2-norbornene by using a catalyst Mo(N-2,6-C6H3-i-Pr)(CHC(CH3)3)(OC(CH3)3)2 was a crystalline polymer having a melting point of 218xc2x0 C. (Metathesis Polymerization of Olefins and Polymerization of Alkynes, NATO ASI Series, p265-276 (1998), Kluwer Academic Publishers). This crystalline polymer tends to be of poor utility for use for which high mechanical strength, good solvent resistance and high heat resistance are required.
In Japanese Unexamined Patent Publication No. S53-17700, a dicyclopentadiene polymer which was crystalline or crosslinked was referred to as an explanation of prior art. This polymer was reported in this publication as being carbonized and decomposed without melting upon heating to a temperature of 200xc2x0 C. to 400xc2x0 C., and thus, as possessing no practical utility and being incapable of being melt-shaped by an ordinary shaping method.
A primary object of the present invention, there are provided a crystalline ring-opened norbornene polymer and a hydrogenation product thereof, which have high mechanical strength, good chemical resistance, good processability and shapability, and high heat resistance; and a process for producing the norbornene polymer and hydrogenation product thereof.
By research to solve the problems of prior art, the present inventors found that, when a polycyclic norbornene monomer such as dicyclopentadiene is polymerized by using a polymerization catalyst comprising as a main ingredient a metal complex containing a transition metal of group 6 of the periodic table and having specific substituents, a ring-opened norbornene polymer is obtained which is a thermoplastic straight-chain ring-opened polymer exhibiting high stereoregularity and having crystallinity and being soluble in chloroform and other solvents; that a hydrogenation product of the ring-opened polymer also is crystalline; and further that the ring-opened polymer and the hydrogenation product thereof have good processability and shapability, high mechanical strength, good heat resistance and good chemical resistance.
Further, it was found that, when a polycyclic norbornene monomer is polymerized by using a polymerization catalyst comprising as a main ingredient a metal complex containing a transition metal of group 6 of the periodic table and having other specific substituents, a ring-opened norbornene polymer is obtained which is non-crystalline but, when hydrogenated, gives a crystalline hydrogenation product.
Still further, it was found that, in the case where a crystalline hydrogenation product of ring-opened norbornene polymer comprising norbornene monomer units is produced, when a polymerization catalyst comprising as a main ingredient a metal complex containing a transition metal of group 6 of the periodic table and having specific substituents is used, the resulting hydrogenation product exhibits higher stereoregularity and has a melting point much higher than those of the known hydrogenation products of ring-opened norbornene polymers.
Based on the above-mentioned findings, the present invention has been completed.
Thus, in one aspect of the present invention, there is provided a ring-opened norbornene polymer comprising at least 10% by mol of repeating units derived from a polycyclic norbornene monomer having at least three rings, in the repeating units of the polymer, said polymer having a weight average molecular weight in the range of 500 to 1,000,000 as measured by gel permeation chromatography and expressed in terms of polystyrene, and having a melting point.
In another aspect of the present invention, there is provided a hydrogenation product of a ring-opened norbornene polymer obtained by hydrogenating a ring-opened norbornene polymer comprising repeating units derived from a polycyclic norbornene monomer, said hydrogenation product having a weight average molecular weight in the range of 500 to 1,000,000 as measured by gel permeation chromatography and expressed in terms of polystyrene, and having a melting point of 140xc2x0 C. or higher.
In still another aspect of the present invention, there is provided a hydrogenation product of a ring-opened norbornene polymer obtained by hydrogenating a ring-opened norbornene polymer comprising at least 10% by mol of repeating units derived from a polycyclic norbornene monomer having at least three rings, in the repeating units of the polymer; said hydrogenation product having a weight average molecular weight in the range of 500 to 1,000,000 as measured by gel permeation chromatography and expressed in terms of polystyrene, and having a melting point.
In a further aspect of the present invention, there is provided a hydrogenation product of a ring-opened norbornene polymer obtained by hydrogenating a ring-opened norbornene polymer comprising repeating units derived from a polycyclic norbornene monomer having two rings in the repeating units of the polymer; said hydrogenation product having a weight average molecular weight in the range of 500 to 1,000,000 as measured by gel permeation chromatography and expressed in terms of polystyrene, and having a melting point of 140xc2x0 C. or higher.
In further aspects of present invention, there are provided processes for producing the above-mentioned ring-opened norbornene polymer and hydrogenation products thereof, which comprise a step of polymerization carried out by using a polymerization catalyst comprising as a main ingredient a metal compound containing a transition metal of group 6 of the periodic table and having at least one imide group and at least one substituent (A) selected from the group consisting of an alkoxy group, an aryloxy group, an alkylamide group and an arylamide group.